The long range purpose of this project is to find out what the ultimate carcinogenic metabolite of benzo(a)pyrene is. The steps toward this goal are: (1) to understand the detailed metabolic profiles of benzo(a)pyrene formed by mixed-function oxidases; (2) to determine the chemical identity of the metabolites; (3) to synthesize the identified metabolites in large quantity; (4) to test the carcinogenic and mutagenic activity of the metabolites.